Date: Tue, 13 Oct 2009 09:58:21 -0500 (CDT) From: Larry Rosenman <ler@lerctr.org> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-stable@freebsd.org Subject: Re: Extreme console latency during disk IO (8.0-RC1, previous releases also affected according to others) Message-ID: <alpine.BSF.2.00.0910130957540.26159@thebighonker.lerctr.org> In-Reply-To: <hb23i7$opq$1@ger.gmane.org> References: <E316139E-FFCF-432F-8DCE-62B120C38E55@exscape.org> <CC16B639-7A75-4016-A8A8-5C59E9CD5E95@exscape.org> <hb1qs0$qjd$1@ger.gmane.org> <alpine.BSF.2.00.0910131406340.26071@fledge.watson.org> <9bbcef730910130633w150571a0k461fb4e67a51fb1d@mail.gmail.com> <B5BA3ACC-BC06-4042-8434-0D9395A0F478@freebsd.org> <hb23i7$opq$1@ger.gmane.org>
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On Tue, 13 Oct 2009, Ivan Voras wrote: > Robert N. M. Watson wrote: >> >> On 13 Oct 2009, at 14:33, Ivan Voras wrote: >> >>>> If (1) is highly variable during I/O, it's almost certainly a property of >>>> the VM technology you're using, and there's nought to be done about it in >>>> the guest OS. >>> >>> Here's an example of a ping session with 0.1s resolution during a few >>> seconds-stall in ssh: >>> >>> 64 bytes from 161.53.72.188: icmp_seq=1576 ttl=64 time=0.383 ms >>> 64 bytes from 161.53.72.188: icmp_seq=1577 ttl=64 time=0.405 ms >>> 64 bytes from 161.53.72.188: icmp_seq=1578 ttl=64 time=0.360 ms >>> >>> 64 bytes from 161.53.72.188: icmp_seq=2304 ttl=64 time=4.194 ms >>> 64 bytes from 161.53.72.188: icmp_seq=2305 ttl=64 time=0.454 ms >>> 64 bytes from 161.53.72.188: icmp_seq=2306 ttl=64 time=0.376 ms >>> >>> note huge packet loss. It looks like it's VM fault or something like it. >> >> It sounds like the VM is failing to execute the guest during certain types >> of I/O. A bit of scheduler tracing in the host OS probably wouldn't go >> amiss to confirm that the VM really is suspending the guest > > It's VMWare ESXi underneath, which is *Officially Not Linux* though some > ducks may disagree - anyway, I suspect tracing the host in this way is next > to impossible without some kind of diamondium-level contract. > What information do you need? I have a platinum VMWare contract. What version of ESXi? LER > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" > -- Larry Rosenman http://www.lerctr.org/~ler Phone: +1 512-248-2683 E-Mail: ler@lerctr.org US Mail: 430 Valona Loop, Round Rock, TX 78681-3893
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